Valve-operating mechanism



C. W, VAN RANST VALVE OPERATING MECHANI'SM Filed Aug. '7.` 1923 2 Sheets-Sheet l .Fuy 8, 1924. 1,500,166

c. w. VAN RANST VALVE OPERATING MECHANISM Filed Aug. 7, 1925 2 Sheets-Sheet 2 Patented dy d, i924,

VALVE-PERATING MEC 1:5 l.

Filtr- Application filed ug'ust 7, 1923. Serial lilo. 656,194.

To all whom t may concern:

Be it known that l, CORNELIUS `W. VAN RANST, a citizen of the United States of. America, residing at Detroit, in the county 5 of Wayne and State lof Michi an, have invented certain new and useul improvements in Valve-Qperating Mechanism, of which the following is a speciication, reference being had therein to the accompanying le drawings. l f

rlhe invention relates to a valve operating mechanism of a construction particularly adapted for use with internal combustion engines of the -V-typehaving a small included i5 ngle between the opposite banks of cyliners. i y

ln in construction, l employ a single cam shaft or actuating the inlet and exhaust valves for all of the cylinders, using'roclrer 2o arms for transmitting the movement from the cams to the valves.

The primary object of my invention is to obtain a construction in which the inlet valves in opposite banks of `cylinders are.

25 held open for the same periods of time. in their respective cycles and are accelerated and dre-accelerated at the same rates. To obtain these. results, l have employed the novel features or" construction which are,

so hereinafter fully described.-

ln the drawings Figure l is a transverse section through an internal combustion engine;

Figure 2 is a diagram illustrating the 35 movements of the rocher arm rollers;

Figure 3 represents the acceleration curves or the valves; l

Figure Il Shows two superposed canister actuating the inlet valves on opposite sides s@ oli the cam shaft illustrating the diderence in their'proles. l

A represents a c linder block having the opposite-sets ol cylinder bores B and B arranged at a slight inclination to the vertical.

se C is a cylinder head suitably secured to the cylinder block and provided with guides -D for the inlet valves E and E' which are Syetrically arran ed on opposite sides of tue median line ont t e engine tov communicate respectively with the cyders B and B.,

is a cam shalt ionrnaled in the cylinder head and arranged longitudinall therewith- 1 in. Gr 'and Gf are rockers coaxia ly'niounted upon `e econ shalt lil erred above the earn shaft @ne end ol each rocker arm engages the stem ci the valves E and E while the opposite end of the rocker arm-is arranged at an angle thereto and provided with a roller l for engaging the cam shaft F. .l and J are cams longitudinally spaced 60 upon the cam shaft F to engage the rollers of the respective rockers G and G.

With a construction as described, the rotation of the camshaft F causes theopeny mg and closing of the inlet valves E and E @p5 by theriding of the rollers l upon the respectlve cams J' and d. ln the usual typeof cam shaft all of vthe inlet cams are of exactly the same contour in order that the inlet valves swill be opened for the same l@ periods of time in the respective cylinders.

l have discovered, however, that it the inlet cams .l and. J are made of the identical contour, the valves E and F are not opened uniformly but that there is considerable le variation in their acceleration. This is due to the angularity of the rocker arms since they are disposed upon opposite sides ol the rotating cam shaft F. Referring now to Figure 2, it the cams l2 and el? are oil thee@ same contoilr, Ithe rollers l land l will be` actuated from the positions K and K to L and L respectively. This results in an angular movement of the roller l! in a clockwise direction through the angle M and acorresponding counter-clockwise rotati'ohnoi the roller l through'the angle l/l. "lhe cam shaft F, however, always rotates in one directlon, for instance, counter-cloclrwis'e. Therefore, the engagementfof the cam 172199 and roller l causes the acceleration of the roller at a diderent rate from lthe roller l., Figure 3 illustrates theacceleration curves of the opposite inlet valves when cams of identical contour are employed, the line N representing the curve ci the roller and the curve N representing the roller l. V ln order to (overcome the diiculty above mentioned l have provided cams or didn-arent contour for actuating the inlet valves cr.' cp- .L posite sides of the cam shalt and these cams are so proportioned that identical accelera tion curves are obtained, thereby insuring uniformity in performance yof the different cylinders of the engine. Als shown in liig-l ure ll,"the cams J and dare considerably diderent in their profile but lwhen arranged on the cam shalt to cooperate with the oppositely arranged rocker arms G and Gf the inlet valves E and F are opened exactly the same amount andl at the same rate ci* acceleration`1 i e c mi at li claim as my invention is 1. In an internal combustion engine, the combination, with a cam shaft and an inlet valve on each side thereof, of a pair of coi axially mounted rockers engaging the respective valves, and separate cams on said cam shaft engaging the respective rockers, said cams having dlerent Acontours such as to impart the same opening andgclosing movement to the opposite valves.

inlet valves in said cylinders, a pair of rockers engalging the respective valves and symmetrica y arrd with respect to said cam shaft, and septe cams on saldcam shaft engaging the respective rockers, said cams having different contours such as to compensate for the angularity of said rockers and impart identical acceleration to the opposite valves.

3. In an internal combustion engine, the combination with a air of inlet valves, a pair of actuating roc ers for said valves, a cam shaft extending transversely to said rockers atequal distances from said valves,

rollers mounted upon said rockers, and separate cams upon said cam shaft engaging.

said rollers, `said cams having dilerent contours of such form as to impart the same openin and closing movements to the opposite va ves.

In testimony whereof I ax my signature. CORNELIUS W. VAN

RANST. 

